1. Field of the Invention
The present invention is related to an automatic sprinkler of fire detector type and sprinkler system including the automatic sprinkler of fire detector type.
In particular, this invention is related to an automatic sprinkler of fire detector type that has not only its inherent function to make opening by itself when a fire occurs, but also a function of electric switch similar to an ordinary fixed-temperature fire detector, and the sprinkler system that includes the automatic sprinkler of fire detector type. More particularly, the above sprinkler system can detect a fire in a freely established area with one or more sprinklers where sprinkler opens.
2. Description of the Prior Art
In general, two types are found in sprinklers; one is closed-type sprinkler and the other is open-type sprinkler.
The closed-type sprinkler includes a heat-actuated element in itself that normally seals a water discharge orifice and is separated by itself from the sprinkler by heat from a fire, and so the closed-type sprinkler is called xe2x80x98automatic sprinklerxe2x80x99 in most literatures of fire protection.
There are various kinds of existing automatic sprinkler, but two operating modes may be found in all automatic sprinklers; one sprinkler can not re-close by itself once opened by heat, but the other sprinkler to be usually called xe2x80x98on-off sprinklerxe2x80x99 can automatically repeat opening and closing in turn by a rise or drop in ambient temperature in the course of fire control.
The automatic sprinkler of non-reclosable type has a heat-actuated element to be fusible or frangible by heat. The fusible heat-actuated element that holds a small quantity of metal to be fusible at a predetermined temperature normally seals a water discharge orifice of sprinkler and then the water discharge orifice is opened when the fusible heat-actuated element is separated from the sprinkler due to melting of the metal by heat. The frangible heat-actuated element that holds a glass bulb containing some liquid of good thermal expansion property normally seals a water discharge orifice of sprinkler and then the water discharge orifice is immediately opened when the bulb is broken by the expanding pressure of liquid generated in the bulb at a predetermined temperature. Typical on-off sprinkler usually has two thermal elements; one is a frangible bulb to initially open the sprinkler orifice and the other is a pilot valve leading to the repeat of opening and closing of a water discharge outlet according to actuation of bimetallic disc by a rise or drop in ambient temperature in the course of fire control. The opening of pilot valve allows water to flow from the sprinkler. When the sprinkler discharge suppresses the fire so the temperature of bimetallic disc drops, the pilot valve is closed and then the waterflow stops.
FIG. 1 shows an outlined drawing of an exemplification of existing automatic sprinkler. And FIG. 2 is a drawing to show that the sprinkler in FIG. 1 opens with separation of fusible heat-actuated element. Such a sort of sprinkler(11), which has been used for a long time, is composed of three essential parts, one of which is a heat-actuated element(17) to be fusible that normally seals a water discharge orifice(13), another is a metallic framed-body(12) with a water discharge orifice(13) and the other is a deflector(15) for dispersion of water discharged out of the water discharge orifice(13) on the other side of water discharge orifice(13). The fusible heat-actuated element(17) tightly seals the water discharge orifice(13) by driving a screw(16) in the center of deflector(15). The fusible heat-actuated element(17) is shaped by assembling several components, one of which is the fusible metal to be previously mentioned, not shown in the drawing, is included. The separation of fusible heat-actuated element(17) from the sprinkler is occurred simultaneously with disassembly of the fusible heat-actuated element(17) since mechanical balance built up among the components of fusible heat-actuated element(17) is lost when the fusible metal held in the fusible heat-actuated element(17) is melted by heat. And the automatic sprinkler of framed-body type is the most commonly used in many countries in the world. The metallic framed-body may have two or more frames(14). An orifice-sealing disc(18) and a disc-supporting metal(19) of round type can be positioned between the water discharge orifice(13) and the fusible heat-actuated element(17).
However, any of all existing automatic sprinklers does not have a mechanism in itself to directly actuate electric circuit that may be introduced for supervisions of sprinkler system such as fire detection, fire indication and fire alert, etc. as shown in ordinary fire detection systems, and so supplemental fire detection system or means for detecting a waterflow to be initiated by discharge of water or air (or nitrogen) from opened sprinkler has been utilized over years for detection of a fire in sprinklered area.
The wet pipe sprinkler system in FIG. 3, the dry pipe sprinkler system in FIG. 4 and the preaction sprinkler system in FIG. 5 are the most typically and widely used among the various existing automatic sprinkler systems.
In the automatic sprinkler systems, one or more water supplies, system pipings and automatic sprinklers are the essential requirements, however, there are various differences between them in system design feature and functional aspect. And, fire water may be obtained from a public or private water source, and in a water supply with a private source, water tank or pond is usually required while associated with fire pump. Such a water tank connected to fire pump as shown in the drawings is primarily necessitated, but an auxiliary tank such as an elevated tank may be included as a supplementary water source. There are various design features in configuration of water supply for sprinkler system, being influenced by infrastructures and circumstances given to a sprinklered building or structure, however, a primary water tank associated with a fire pump and a pressure maintenance pump, and a supplementary elevated tank(23) are examplified for water supply to the sprinkler systems shown in FIGS. 3, 4 and 5. The pressure maintenance pump is employed to make up water pressure in system pipings since a pressure drop in the system pipings to be initiated by water discharge from opened sprinkler can be utilized for automatic operation of the fire pump. In this case, pressure switches are usually used to detect the pressure drop or rise for starting or stopping the fire pump and the pressure maintenance pump.
In such the wet pipe sprinkler system as shown in FIG. 3, all pipings(21) always contain water and are connected to water supply so that water discharges immediately from the sprinklers(11) opened by heat from a fire. The wet pipe sprinkler system is the simplest and the most reliable of all the sprinkler systems, but it is undesirable to employ this system in the sprinklered area to be subject to water freezing.
In the wet pipe sprinkler system, a waterflow detecting device(31) to be called xe2x80x98alarm check valvexe2x80x99 is the most commonly employed on a system riser pipe(54) to detect opening of sprinkler(11), that is, the opening of sprinkler lets water discharge into the fire area and in turn the water flowing to the opened area through the system riser pipe activate the waterflow detecting device(31).
And, a test-connection(26) examplified in FIGS. 3 and 4 is usually installed to routinely test the performance of waterflow detecting device.
As shown in FIG. 4, the dry pipe sprinkler system developed to meet the need for sprinkler protection in unheated occupancies or structures has a dry pipe valve(25) on a system riser pipe(54), and all system pipings(21) above the dry pipe valve(25) do not contain water but air or nitrogen under pressure. The air or nitrogen pressure restrains the water in the water supply main at the clapper arrangement (not shown in the drawing) of the dry pipe valve(25), and the release of pressurized air or nitrogen, which is initiated prior to discharge from the opened sprinkler(11), permits the water pressure in the water supply main to open the dry pipe valve(25). The water then flows into the system pipings(21) above the dry pipe valve(25) and out of the opened sprinkler(11). The dry pipe valve(25) also has a waterflow detecting function similar to the alarm check valve to be employed in the wet pipe sprinkler system. An air compressor(27) should be employed to make up air pressure in system pipings.
As shown in FIG. 5, the preaction sprinkler system employs a deluge valve(32) on a system riser pipe(54) that is normally closed in non-fire situation, and the automatic sprinklers(11) attached to the system pipings(21) containing air that may or may not be under pressure, together with supplemental fire detection systems(34) including fire detectors(33) which are installed in the same area as the sprinklers(11) for operation of deluge valve(32).
Actuation of the fire detection system(34) opens the deluge valve(32) that permits water to flow into the system pipings(21) and be discharged from any sprinklers(11) that are open. The deluge valve(32) may or may not have a waterflow detecting function, relying on design feature of system(34) and arrangement of trimmings to be associated with the deluge valve(32).
The water supply including water tank(22) and fire pump(24) is widely introduced in many sprinkler systems, and in this case, it is usual to provide automatization in operation of fire pump(24).
Automatic operation of fire pump(24) in sprinkler systems may be possible by means of detection of a waterflow in system pipings(21) or a drop in water pressure in system pipings(21) that is caused by water discharge due to opening of sprinkler(11), however, automatic operation of fire pump(24) in the preaction sprinkler system may be initiated by actuation of fire detection system(34) accompanied with the preaction sprinkler system, but this is not frequent on account of a real frequency in false operation or malfunction of customary fire detectors(33).
It is usual that supervisions such as fire detection, fire indication and fire alerts, etc. to be needed in wet pipe sprinkler system or dry pipe sprinkler system, though control for operation of fire pump(24) is occasionally included, are initiated by activation of waterflow detecting device(31), and in preaction sprinkler system, by actuation of fire detection system(34) or activation of waterflow detecting device(31) or both. However, in many sprinkler systems, automatic operation of fire pump(24) is initiated by actuation of pressure switch(30) that detects a drop or rise in water pressure in system pipings(21) to be generated when water discharges from opened sprinkler, and in this case, pressure maintenance pump(28) may be quite often employed to pressurize water in system pipings(21).
It is noted that a waterflow detecting device(31) or other device with waterflow detecting function can not addressably detect opening of every sprinkler, neither can it detect opening of sprinkler in every area to be freely established and protected by two or more sprinklers. In other words, the above device can not addressably detect every area to be freely established and protected by one or more sprinklers. Therefore, if trying to make such an addressable fire detection to be possible, a waterflow detecting device(31) or a fire detector(33) of addressable type should be individually joined with every sprinkler or every area to be freely established, but it might not be practical on account of a demand of much money as well as more complicated systemization.
The first object of the present invention is to provide an automatic sprinkler having both a function of fire detector similar to a fixed-temperature fire detector that the existing automatic sprinkler does not have and its inherent function of automatic opening for water discharge.
The second object of the present invention is to provide a sprinkler system that can make addressable supervisions such as addressable fire detection, fire indication and alert of fire, etc. to be initiated by actuation of automatic sprinkler of fire detector type installed in sprinkler system.
The third object of the present invention is to provide a sprinkler system that can make operating equipments or devices such as fire pumps and fire alarm initiating devices to automatically operate by actuation of automatic sprinkler of fire detector type without any pressure maintenance pump and pressure switch.
The fourth object of the present invention is to provide a sprinkler system of intelligent type that may discharge water into a fire area with application density to be adjustable that can be obtained by RPM adjustment of a fire pump with a speed-changeable driving-motor that is controlled by a computer to be hydraulically pre-programmed according to the number of opened sprinklers in the fire area.
The fifth object of the present invention is to provide a sprinkler system that can satisfactorily detect a fire even with no waterflow detecting device.
The sixth object of the present invention is to provide a simple sprinkler system that is available for protection of unheated sprinklered area; in the above sprinkler system a deluge valve that can be opened by actuation of automatic sprinkler of fire detector type is employed on a system riser pipe, and the opening of the deluge valve can allow water to flow into system pipings that are always maintained empty without air-pressurization, and then the water is discharged from opened sprinkler.
The seventh object of the present invention is to provide a sprinkler system more reliable than all existing sprinkler systems, in a point of view that operation of the sprinkler system in accordance with the present invention is initiated by the opening of automatic sprinkler of fire detector type that is rarely occurred accidentally in non-fire situation when compared with real frequency of accidental activation or malfunction of ordinary fire detector or waterflow detecting device in non-fire situation.
A further object of the present invention is to provide a sprinkler system that can take care and maintenance to be more convenient and economical than the existing automatic sprinkler systems.
It is to be noted that both the foregoing general description and the following description in detail are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.